Individualized screening for chaperone activity in Gaucher disease using multiple patient derived primary cell lines

The knowledge of individual response to a therapy, which can be assesed by in vitro screening, is essential for the development of therapeutics. Chaperone therapy is based on the ability of small molecules to fold the mutant protein to recover its function. As a novel approach for the treatment of Gaucher disease (GD), ambroxol was recently identified as a chaperone for GD, caused by the pathogenic variants in GBA gene, resulting in lysosomal enzyme glucocerebrosidase (GCase) deficiency. Since ambroxol activity is mutation-dependent, the assessment of the chaperone action requires adaptation of a cell model with genetic format identical to the patient. We compared the chaperone activity of ambroxol using different primary cells derived from GD patients with different GBA genotypes. Ambroxol enhanced GCase activity in cells with wild type GBA and in those, compound heterozygous for N370S, but was ineffective in cell lines with complex GBA alleles. In cells from patients with neuropathic GD and L444P/L444P genotype, the response to ambroxol was varied. We conclude that chaperone activity depends on diverse factors in addition to a particular GBA genotype. We showed that PBMCs and macrophages are the most relevant cell-based methods to screen the efficacy of ambroxol therapy. For pediatric patients, a non-invasive source of primary cells, urine derived kidney epithelial cells, have a vast potential for drug screening in GD. These findings demonstrate the importance of personalized screening to evaluate efficacy of chaperone therapy, especially in patients with neuronopathic GD.